The present invention is an electropolishing process device for inner and outer surfaces of a metal, more specifically for cleaning and passivation of the inner and outer surfaces of the metal.
A process of electropolishing is to connect a workpiece to an anode and a metal to a cathode, aforesaid whole structure of workpiece connecting to anode and electrode connecting to cathode is put into electrolyte for electrifying direct current, thus defects on workpiece surface are removed to produce a surface that is shining and smooth. Benefits of electrolysis and polish improving surface cleanness, roughness, passivation, etc. Industry, such as semiconductor, chemical industry, biochemical engineering, food industry, need tubes to deliver fluids, and inner surfaces of tubes are treated by polish or electrolysis to approach high cleanness and anti-corrosion. Especially, products of IC/LCD/III-V require high standards of cleanness and anti-corrosion, thus, applying the present invention to said products is a challenge.
In prior arts of U.S. Pat. No. 4,826,582 and 4,849,084, which taught a Dart of the technologies for electropolishing a 10-meter heat exchange tube, utilized an electrode device for positioning a workpiece and required sealing an electrolyte. The prior arts adopt a 3-layer structure of delivering electrolyte of high pressure air, but unfortunately said structure is very complicate and only suitable for the larger diameter workpieces, not for the tube of inside diameter under 3 cm.
The prior art of U.S. Pat. No. 5,958,195 taught the technology of electropolishing an inner surface of a long and bent tube. However, to electropolish a bent tube, an electrode must move alone along a curve and prevent short circuit. The most important parts are a flexible electrode and an insulation device. The insulation device is to avoid short circuit and non-concentricity, but this kind of devices block electrolyte flowing and make an un-average electric field. etc.
The prior art of U.S. Pat. Nos. 4,601,802 and 4,705,611, disclose a fixture applied inside a tube, and the fixture stabilizes a plurality of axially rotating tubes simultaneously. An end connector can circulate tube and exhaust gas from an upper end, and electrolyte can be recycled after overflowing. An electrode length is equal to the tube length, therefore a huge space and a super power supplier are needed for such conditions.
Based on the aforesaid issues, the present inventor of the invention has studied and referred to practical experiences and theory to design and effectively improve the prior arts.
The first object is to offer an electropolishing process means for inner and outer surfaces of a metal, which improves an electrode design and applies theories of macro and micro polishing to an electrode means for improving a manufacturing rate in both smoothing and passivation effect on the surface of workpiece.
The second object is to offer an electropolishing process means for inner and outer surfaces of a metal, which can treat both inside and outside of a workpiece simultaneously, and the workpiece inner diameter is smaller than one inch. The device has a simple structure that will save on equipment cost.
The third object is to offer an electropolishing process means for inner and outer surfaces of a metal, which avoids short circuit and non-concentricity problems. An electrode of the present invention is installed through a center of the workpiece, so the electrode has a certain distance with the inner surface of the workpiece. Therefore, the short circuit and non-concentricity are solved.
The appended drawings will provide further illustration of the present invention, together with description; serve to explain the principles of the invention.